Experimental Strain Field Assessment of Pressure Armor Profiles Subjected to Compression Loads via Digital Image Correlation

Abstract The pressure armor layer of a flexible pipe is designed mainly to resist radial loads. Despite the diversity of analytical and numerical studies, some absence of experimental results to evaluate the behavior of this reinforcement layer may be noted. One of the reasons for this lack of experimental studies is the difficulty in accessing and instrumenting this structural layer, particularly when internal contact strain fields are concerned. This study proposes a simple experiment to assess the strain fields of typical pressure armor wire profiles subjected to compressive loads. Using a DIC (Digital Image Correlation) system, the experimental campaign aims to map the strain distribution in a 2:1 scaled sample of a typical wire profile. This technique allows identifying maximum strain values in the cross-sections and more specifically in the contact regions between the pressure armor wires. The obtained experimental results are not yet conclusive. Nonetheless, they provide some interesting insights for a better understanding of the structural behavior of the pressure armor layer. Its findings are valuable for academia and the industry and could serve as a starting point to assess the complex problem of determining cross-sectional strains (and stresses) in pressure armors.